Fiqh-us-Sunnah Volume 4, Funerals and Dhikr, Fiqh 4.107.

Section : Warning Against Sitting in Company Where Allah is Not Mentioned and Blessings on His Prophet are Not Invoked.

Abu Hurairah reported that the Prophet, peace be upon him, said, “If people sit in an assembly in which they do not remember Allah nor invoke a blessing on the Prophet, it will be a cause of grief for them on the Day of Judgment.” This is reported by Tirmizhi, who says it is a sound hadith.

In the version of Ahmad, however, we read, “If people sit in an assembly in which they do not remember Allah, it will be a cause of sorrow for them, and if a man is walking and does not remember Allah, it will be a cause of sorrow for him, and if a man lies down on his bed and does not remember Allah, it will be a cause of sorrow for him.” Another version says, “It will be a sorrow for them, even if they are given Paradise in reward.”

The author of Fath al-‘Allam says, “This hadith proves that it is incumbent on one to remember Allah and invoke blessings on the Prophet while sitting in an assembly, for whether we take the words ’cause of grief or sorrow’ to mean torment of fire or any other chastisement, obviously a punishment is incurred only when an obligatory act is neglected or a forbidden act is committed, and here it is both the remembrance of Allah and the invoking of blessings on His Prophet that are apparently incumbent.”